/Engine/Source/Runtime/GeometryCore/Public/Generators/SweepGenerator.h
Utility function for calculating the triangle normal contributions to average normals.
void AdjustNormalsForTriangle ( int32 TriIndex, int32 FirstIndex, int32 SecondIndex, int32 ThirdIndex, [TArray](API\Runtime\Core\Containers\TArray)< FVector3d > & WeightedNormals )